Covid cases increase in parts of the US, but not hospitalizations 3:49
(CNN) --
A recent outbreak of Covid-19 cases among officials in Washington, with dozens of people testing positive after attending the Gridiron Club dinner, has brought the concept of COVID-19 superspreading back into the spotlight. covid-19.
Covid-19 superspreading, which involves the virus spreading in a single event on a larger scale than normally expected, is still possible and poses a risk.
But at this stage of the pandemic, a major event may not necessarily be an invitation to widespread, uncontrolled disease, if people use the tools now available to limit risk, according to public health experts.
Now, there are more tools to slow the spread of covid-19: licensed vaccines that limit disease and infections, robust supplies of home tests that can tell if someone needs to isolate, face masks to wear in high-risk situations, and treatments that can reduce severe disease.
"We used to be concerned that these superspreading events would put a lot of people in hospital and as a consequence some people in intensive care units and even some people dying. This is less likely to happen now," said Dr. William Schaffner, a professor from the Division of Infectious Diseases at Vanderbilt University Medical Center.
"Given the level of natural immunity, as well as vaccination in our communities, most infected people will now develop a mild illness that does not require them to be hospitalized."
Meanwhile, it is also more complicated to link Covid-19 cases to specific events.
Contact tracing has all but disappeared, and people can encounter covid-19 in any circumstance as workplaces, stores and restaurants reopen and masks are removed.
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But by using the right tools at the right times, there is hope that superspreading of covid-19 will become a thing of the past.
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Covid cases increase in parts of the US, but not hospitalizations 3:49
"The pandemic is not over"
Early in the COVID-19 pandemic, superspreading at business conferences, political events, and even choir practice helped shape understanding of just how transmissible the coronavirus might be.
In one case, 200 people attended a biotech conference in late February 2020 and may have been linked to some 20,000 cases of Covid-19 in the Boston area, according to research from the Broad Institute of MIT, Harvard University. and other institutions.
A report released by the US Centers for Disease Control and Prevention (CDC) in May 2020 described how a symptomatic person with COVID-19 attended a choir practice in Washington state .
Subsequently, about 87% of the other members of the choir developed covid-19.
But those superspreading events happened before it was clear exactly how the virus spread and who was most at risk, and long before Covid-19 vaccines were available in December 2020.
"The pandemic is not over. We are still going to see cases of this virus spreading, and we have to continue to be vigilant. We have to continue to be careful," Dr. Ashish Jha, the new coronavirus response coordinator at the White House on ABC's "Good Morning America."
Jha said he is not aware of anyone becoming seriously ill after the Gridiron dinner in Washington.
"As long as people are vaccinated and have the boosters, we now have plenty of treatments available. Let's put that together. The good news is that no one outside of that so far has gotten particularly sick."
"And that's what we have to keep track of, making sure that when there are outbreaks, we can take care of people," Jha added.
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Some infectious disease experts argue that despite increased access to vaccines and testing, the Covid-19 superspreading events are not over.
"I think this event in Washington was similar to a superspreader event. It was clearly an event where people came together, and the virus came out and made itself known to a lot of people and infected people," Schaffner said.
Covid-19 superspreading events are not "a thing of the past," he said.
"So they still happen? Of course. How important are they? Well, they put quite a few people out of commission for a while, at least having to isolate at home because they were infected."
The United States is averaging more than 38,000 Covid-19 cases per day and about 545 deaths per day, according to CNN analysis of data from the CDC and Johns Hopkins University.
The Department of Health and Human Services says there are more than 14,700 people hospitalized with covid-19.
About 66% of the US population is fully vaccinated.
"While I don't think superspreader events will cause sudden increases in hospitalizations, they may continue to increase and accelerate transmission of the virus, causing milder illness in our communities," Schaffner said.
As we transition to living with covid-19 long-term, there will be a greater chance of encountering someone with a mild infection, but still communicable, through everyday activities such as going to school, the office, a neighbor's block party, church, sporting event or a happy hour.
But there are also more possibilities to identify them.
“It is much more likely now than it was two years ago to find people who are positive but asymptomatic,” said Dr. Georges Benjamin, executive director of the American Public Health Association.
But identifying multiple cases at the same time in the same place doesn't necessarily mean all of those people were infected at the same event.
"Is it a superspreading event? Some of them may have been infected elsewhere before they met, unless of course they get tested before they leave," Benjamin said.
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"Outbreaks" of coronavirus can occur
The concept of a superspreading event is "not new," said Keri Althoff, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health.
"In the story, we identified individuals who were superspreaders," he said.
"For example, Typhoid Mary."
The worldwide understanding of superspreading events dates back to Mary Mallon, commonly known as "Typhoid Mary".
Mallon was born in Ireland in the late 1860s and emigrated to the United States, where she worked in a variety of domestic jobs for wealthy households before becoming a cook.
Investigators discovered that Mallon unknowingly carried the bacteria Salmonella typhi, which causes typhoid fever.
As a cook, she spread the disease to others, leading to an outbreak in New York.
"She infected hundreds, if not thousands, of people with typhoid fever because she carried it in her gallbladder and worked as a cook. Wherever she went, people were getting sick," said Dr. Preeti Malani, director of health for the Division of Infectious Diseases from the University of Michigan at Ann Arbor.
The New York Department of Health forced Mallon to self-quarantine.
“She was in exile for decades because she kept infecting others with typhoid fever,” Althoff said.
"She was asymptomatic."
Mallon's case is an example of how pathogens can spread on a large scale, leading to a superspreading event.
But it's also an example of how the term "superspreader" can isolate and stigmatize those who carry pathogens, even without knowing it.
In the case of Typhoid Mary, the term "super-spreader" was used to describe one person, while more recently the term is used to describe an event during which many people become infected, probably from more than one infected person in the event.
Many experts call the term problematic when it is used to blame a person for having an illness.
Althoff believes the United States is at a point where Covid-19 superspreader events are becoming a thing of the past as the coronavirus circulates widely in our communities.
Events that result in a greater number of infections that might not otherwise have occurred can best be described as outbreaks, Althoff said, similar to how we see outbreaks of other vaccine-preventable respiratory illnesses like measles or the flu.
"Very early in the pandemic, when the number of cases was low, we saw and investigated superspreading events, and those investigations provided important information about the virus when we knew very little," Althoff said.
"Large-scale outbreaks continue to provide insight into how this variant is interacting with a population that has a much higher level of population immunity now than we did at the start of the pandemic."
So now, when clusters of cases come up, "instead of 'superspreader,' I think the word 'outbreak' is a little more reasonable," Althoff said.
"Outbreaks can happen whenever we are in higher-risk environments."
How is covid-19 spreading now?
Although "superspreading" events were considered drivers of Covid-19 transmission early in the pandemic, they are now "much less of a concern," according to Malani.
"Much of the transmission during the omicron era and the BA.2 subvariant has been household contact, where the whole family or their household gets infected. But really, what I see, and I emphasize over and over again, is that it is in social gatherings where there is no mandatory use of masks, that infections occur, ”said Malani.
One big difference between social gatherings happening now and weddings, funerals, or choir practices during the early days of the pandemic is that many people now have some immunity to Covid-19 by getting vaccinated, infected, or both.
Based on information from blood samples, about 95% of Americans over the age of 16 have antibodies to Covid-19 as of December, the most recent date for which data is available, according to CDC estimates.
Current COVID-19 vaccines are more effective at preventing severe COVID-19 that leads to hospitalization or death, but they also offer some protection against infection in the first place.
And "keeping up to date with your Covid-19 vaccination also means you are less likely to spread the disease to others and increase your protection against new variants of SARS-CoV-2, the virus that causes Covid-19," according to the CDC.
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"What's happening right now in the pandemic is that people can protect themselves differently," Malani said, adding that now people can gauge their risk of contracting Covid-19 before they attend an event by finding out if others have been tested.
or vaccinated.
Many COVID-19 outbreaks still occur in areas of the United States where there are many unvaccinated people, Benjamin said.
"In those areas of the country, those communities where we still have unvaccinated people and numbers of unvaccinated people, in those cases, we're certainly going to see an increasing number of people testing positive," he said.
Superspreading might be more likely in such communities.
Although superspreading events are no longer as concerning now as they were earlier in the pandemic, "they are still going to happen," Benjamin said.
"They're definitely going to be one of the patterns that we're going to see for some time from the disease, as long as we still have a variant that's highly infectious and a variety of people at various stages of protecting their immunity."
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